2,5 - dihydroxy - monomethyl- or diethyl-aminobenzene for dyeing living human hair,furs and other keratinous fibers



United States P ten Int. (:1. A61k 7/12 US. Cl. 8-10 .2 8 Claims ABSTRACT OF DISCLOSURE Hair dye compositions having improved colorj stability which contain. 2,5-dihydroxy monomethylaminobenzene or 2,S-dihydroxy-diethylaminobenzene or their acid addition salts; and the method'of dyeing keratinic fibers with these compositions. i

' This application is a continuation-in-partof U.S. ap;

plication 207,090 filed July 2,1962. Y

This invention relates to the. dycing of hair, furs and other keratinous fibers.

The known hair-dyeing processes are based almost exclusively upon the'us of a' hammer aromatic paradiamines and aminophe'nols, that is to say, on the use of intermediate bases which are converted by oxidation to it has beenfound that aqueous solutions of 2,4-dihydroxyaminobenzene and of 3,4-dihydroxyaminobenzene, in contradistinction to those of 2,S-dihydroxyaminobenzene, have an inconvenient color instability even at a pH of 7, and that their dyeing power decreases. and may even dis appear at the end of several months.

It has surprisingly now been found that aqeous solutions of certain 2,5-dihydroxyaminobenzene derivatives not only remain stable and do not lose their dyeing properties, but in addition make it possibleto produce particularly valuable shades of coloration of the fibers. This is important since it is well known to be essential in this art to have available a-range of compounds ca pable of producing different variations of shade.

According to the present invention there is provided a process for dyeing live human hair, fur or other keratinous fibers which comprises impregnating said fibers with dyes which have a true dyeing action on;the. fiber, with the aid of modifiers such as metadiamines and phenols or polyphenols. p

The formation, from these mixtures, of the coloring matter which has the dyeingefiect results from a series of very complex chemical reactions... The method necessitates, on the one hand, the use of an xidizing substance, such as hydrogen peroxide, and the presence of a base, such as an alkali hydroxide, ammonia, etc. Consequently, the pH of these dyeing compositions is usually between 9 and 10. r

The aforesaid processes, which areentirely satisfactory from theviewpoint of the dyes and of the shades obtained,

nevertheless have some disadvantages. More especially, the use of paradiamines may sometimes result in slight dermatitis and may produce allergies in some particularly sensitive persons. Moreover, in these processes, the solution of the dyes is usually mixed, a few instants before use, with a dilute hydrogen peroxide solution and the mixture is applied to the hair, This addition. constitutes a complication and is a cause of degradation of the keratin r of the hair. The alkaliwhich, is present in thesedyeing compositions may also give rise to hydrolysis and deterioration of the texture of the hair. i

US. Patent 3,011,858 describes a process for dyeing live human hair, fur and other keratinous fibers which comprises impregnating the fibers with an aqueous solution of at least one dihydroxyaminobenzene selected from 2,5 dihydroxyaminobenzene, 2,4 dihydroxyaminobenzene and 3,4-dihydroxyaminobenzene, and acid addition salts thereof, and subjecting the impregnated fibers to the action of an oxidizing agent. It has been possible by this process to obviate or greatly to lessen, the aforesaid disadvantages.

Using the aforesaid compounds the allergic manifestations are greatly reduced and the use of hydrogen peroxide and alkali is unnecessary. 'It is possible to obtain attractive shades by application of aqueous solutions of these products at a pH value of 7, without any additional oxidizing agent, by simple exposure to the ambient air. However, in the commercial utilization of these products an aqueous solution of at .least one ,compound selected from the group consisting of formula "formula, in contact with the air, the pH of the solution being between approximately 3 and 10. The results are particularly satisfactory when the pH of the solution is approximately 7.

Compounds of the above general formula which are particularly suitable for carrying out the process of the invention are: j

2,5-dihydroxy-monomethylaminobenzene, 2,5-dihydroxy-diethylaminobenzene and 2,5-dihydroxy- B-diethylaminoethyl) -aminobenzene.

' It will be noted 'thatthe method justdescribed does not require the addition of an oxidizing agent, or the provision of alkali because these" compounds may be oxidized by the oxygen in the air. Moreover, the cornpounds usedhave not been found to give rise to allergic reactions in the subjects when applied to human hair.

It is, however, possible when desired to use an oxidizing agent, for example hydrogen peroxide or any oxidizing agentused in this art, and a base,such as analkali hydroxide, ammonia, etc., in order to increase the pH of the dyeing solution. The results are also satisfactory and the colors remain stable.-

It is also possible to add to the aqueous dyeing compositions of this invention the conventional products employed in hair dyeing 'andintended to increase the yield or to produce other effects, such as, for example, wetting agents, thickening agents, foaming agents and reducing agents such as sodium sulphite.

The compounds 2,5 dihydroxy -'monornethylaminobenzene, 2,5 dihydroxy diethylaminobenzene and 2,5- dihydroxy-(/8-diethylaminoethyl) aminobenzene are novel per se and the invention includes these compounds and the processesfor theirproduction, referred to later herein, and also dyeing compositions containing them.

Patented Dec-223,. 1969 3 The following examples will serve to illustrate the invention.

(A) EXAMPLES OF PREPARATION 1 2,5-dihydroxy-monomethylaminobenzene (at) PREPARATION OF 2,5-DIl\IETHOXYN-METHYL- ACE'IANILIDE The corresponding sodamide is prepared in the usual way by introducing 6.32 gram-atoms of sodium into an excess of liquid ammonia. 5.05 mol. of 2,5-dimethoxyacetanilide are then introduced in small portions. The mixture is allowed to stand for 1 hour and 6.56 mol. of methyl sulphate are then introduced over a period of 1 hour. The excess of ammonia is then allowed to evaporate. The remaining residue is taken up in water and extracted with methylisobutylketone. After evaporation of the solvent, there is obtained, in a yield of 92.5%, an oily product corresponding to the desired product, which is directly treated without further purification.

(b) PREPARATION OF THE HYDROBROMIDE OF.

2,5-DIHYDROXY-MONOMETHYLAMINOBENZENE A mixture of 4.66 mol. of 2,5-dimethoxy-N-methylacetanilide and 7 litres of 48% hydrobromic acid is refluxed for 4 hours. The product is thereafter concentrated by evaporation in vacuo, in a nitrogen atmosphere, to about 1.3 litres. The products precipitate on cooling in a mixture of ice and salt. After separation and drying in vacuo at 100 C., the desired hydrobromide is obtained in a yield of 77%. After recrystallization from hydrobromic acid, this product melts at 177-178" C. with decomposition.

Analysis.Calculated for C H O Br, percent: C, 38.19; H, 4.54; N, 6.36. Found, percent: C, 37.72-37.83; H, 4.45-4.53; N, 6.44.

(2) 2,5-dihydroxydiethylaminobenzene (t1) PREPARATION OF 2,5DIMETHOXY DIETHYLANILINE A mixture of 0.2 mol. of ethyl phosphate and 0.2 mol. of 2,5-dimethoxyaniline is heated under reflux for 4 hours. After cooling to 70 C., the mixture is poured into 200 cc. of 13% sodium hydroxide. The whole is refluxed for one and a half hours and, after cooling and dilution with water, extraction is effected with diethyl ether. The product obtained is distilled in vacuo and passes over at 71- 78 C. under 0.07 mm. Hg pressure. The yield is 75%.

(b) PREPARATION OF 2,5-DIHYDROXY-DIETHYL- AMINOBENZENE A mixture of 0.15 mol. of 2,5-dimethoxy-diethylaniline, 34 cc. of glacial acetic acid and 250 cc. of 65% hydrobromic acid is heated under reflux for 4 hours. The reaction mixture is thereafter evaporated in'vacuo and under a nitrogen atmosphere. The desired product is thus obtained in a quantitative yield. The 2,5-dihydroxy-diethylaminobenzene hydrobromide i purified by dissolution in absolute ethanol and reprecipitation by means of diethyl ether. It is a hygroscopic product.

Analysis.-Calculated for C H O NBr, percent: C, 45.80; H, 6.10; N, 5.34. Found, percent: C, 45.54; H, 6 31; N, 5.15.

(3) Preparation of 2,5-dihydroxy-(fi-diethylaminoethyl) aminobenzene (a) PREPARATION OF 2,5-DIMETHOXY-(BDIETHYL- AMINOETHYL) -AMINOBENZENE A solution of 1.75 mol. of the hydrochloride of N-fldiethylaminoethyl chloride in 800 cc. ofwater is added over a period of 2 hours to a mixture, maintained at boiling point, of 1.63 mol. of 2,5-dimethoxyaniline, 0.95 mol. of calcium carbonate and 2.5 litres of water. After cooling and extraction with methylisobutylketone to remove the unconverted products, the reaction mixture is made alkaline by the addition of 200 g. of 40% sodium bydroxide and again extracted with methylisobutylketone. The product is distilled in vacuo. It passes over at C. under 0.1 mm. Hg pressure. The yield is of the order of 78%.

(b) PREPARATION OF 2,5-DIHYDROXY- e-DIETHYL- AMINOETHYL) -A1NIINOBENZENE (B) EXAMPLES OF THE APPLICATION OF THE DYEING COMPOSITIONS Example I The following solution is prepared:

2,5-dihydroxy methylaminobenzene hydrobromide 2.2 Fatty alcohol C -C condensed with 2 mol of etlIylene oxide, sulphated, sodium salt containing 20% of initial hydroxy-ethylenated alcohol g" 4 5 N sodium hydroxide solution, q.s. for pH 7. Water q.s. for cc 100 This solution is applied to grey hair and left in contact with the arr for 20 minutes. After rinsing and drying the hair has a pale golden shade.

Example II In the same way as in Example I, there is prepared a solution containing:

2,S-dihydroxy-diethylarninobenzene hydrobromide 3 Fatty alcohol C -C condensed with 2 mol of ethylene oxide, sulphated, sodium salt containing 20% of initial hydroxy-ethylenated alcohol g 4 5 N sodium hydroxide solution, q.s. for pH 7. Water, q.s. for cc 100 When this solution is applied to grey hair for 20 minutes, and then rinsed and dried, a pink-tinged light blond shade is obtained.

Example III When, under the same conditions as in Example II, there is applied to the hair a solution prepared from:

2,5-dihydroxy (B diethylaminoethyl)aminobenzene dihydrobromide g.' 3.8 Fatty alcohol C -C condensed with 2 mol. of ethylene oxide, sulphated, ammonium salt containing 20% of initial hydroxy-ethylenated alcohol g 4.5 5 N sodium hydroxide solution, q.s. for pH 7. Water q.s. for cc 100 A very natural blond shade is obtained on grey hair.

What is claimed is:

1. A dye composition for live human hair, fur and other keratinous fibers comprising an aqueous solution containing an effective dyeing amount of 2,5-dihydroxymonomethylarninobenzene or its acid addition salt and having a pH of about 3 to 10.

2. A dye composition for live human hair, fur and other keratinous fibers comprising an aqueous solution containing an effective dyeing amount of 2,5-dihydroxydiethylaminobenzene or its acid addition salt and having a pH of about 3 to 10.

3. The composition of claim 1 wherein said compound is in the form of its acid addition salt.

4. The composition of claim 2, wherein said compound is in the form of its acid addition salt.

5. A process for dyeing live human hair, fur and other keratinous fibers which comprises the steps of impregnating said fibers with dyeing amounts of the composition of claim 1 and allowing oxidation of the compound to take place on the fibers by exposing the same to air or an oxidizing agent.

6. The process of claim 5, wherein said compound is in the form of its acid addition salt.

7. The process for dyeing live human hair and other keratinous fibers which comprises the steps of impregnating said fibers with dyeing amounts of the composition of claim 2 and allowing oxidation of the compound to take place on the fibers by exposing the same to air or an oxidizing agent.

8. The process of claim 7, wherein said compound is in the form of its acid addition salt.

6 References Cited UNITED STATES PATENTS 3,011,858 12/1961 Lantz et al 167-88 X FOREIGN PATENTS 1/1960 France.

OTHER REFERENCES Chemical Abstracts, vol. 26, p. 7594 (1932).

ALBERT T. MEYERS, Primary Examiner VERA C. CLARKE, Assistant Examiner U.S. Cl. X.R. 8-11; 260570.5 

